Sexual size dimorphism and sex determination by morphometric measurements in breeding Imperial Shags (Phalacrocorax atriceps)
- Autores
- Svagelj, Walter Sergio; Quintana, Flavio Roberto
- Año de publicación
- 2007
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- The Imperial Shag (Phalacrocorax atriceps) is monomorphic in plumage, but males are larger than females. We analyzed the sexual size dimorphism and variability of six morphometric characteristics (bill length, bill depth, head length, tarsus length, wing length, and body mass) measured on 291 breeding Imperial Shags at Punta León colony in coastal Patagonia, Argentina, during 2004 and 2005 breeding seasons. Discriminant analyses were performed on external measurements that we considered potentially useful in sexing Imperial Shags. All the birds were sexed by a distinctive behavior (vocalizations) and a sub-sample of fifty were also sexed by DNA-based genetic techniques, showing 100% agreement between the two methods. All measured characteristics differed between the sexes, with males being larger than females. Body mass (17.8 - 18.0%) and bill depth (12.8 - 13.2%) showed the highest level of dimorphism whereas bill, head, tarsus, and wing length were less dimorphic (ranging 4.8 - 6.0%). Dimorphism in body mass for breeding shags was lower than previously reported during winter, prior to the breeding season. Although the wing length showed the lowest degree of dimorphism (5.3 - 5.4%), it presented the lowest coefficient of variation (1.9 - 2.0%) resulting in the most accurate single-measurement indicating sex. A cross validation process with a new sample, revealed that discriminant functions comprised by two characteristics were more accurate and reliable for sex determination than single-measurements. We obtained two functions correctly classifying 94 - 97% of shags. These functions were reliable (similar accuracy for discriminant analysis, Jackknifed validation, and cross-validation with a new sample) and seasonal unbiased, as body mass was not included in the analysis.
Fil: Svagelj, Walter Sergio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina
Fil: Quintana, Flavio Roberto. Wildlife Conservation Society; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina - Materia
-
DISCRIMINANT ANALYSIS
IMPERIAL SHAGS
PHALACROCORACIDAE
PHALACROCORAX ATRICEPS
SEXUAL SIZE DIMORPHISM - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
- Repositorio
- Institución
- Consejo Nacional de Investigaciones Científicas y Técnicas
- OAI Identificador
- oai:ri.conicet.gov.ar:11336/102934
Ver los metadatos del registro completo
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network_name_str |
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spelling |
Sexual size dimorphism and sex determination by morphometric measurements in breeding Imperial Shags (Phalacrocorax atriceps)Svagelj, Walter SergioQuintana, Flavio RobertoDISCRIMINANT ANALYSISIMPERIAL SHAGSPHALACROCORACIDAEPHALACROCORAX ATRICEPSSEXUAL SIZE DIMORPHISMhttps://purl.org/becyt/ford/1.6https://purl.org/becyt/ford/1The Imperial Shag (Phalacrocorax atriceps) is monomorphic in plumage, but males are larger than females. We analyzed the sexual size dimorphism and variability of six morphometric characteristics (bill length, bill depth, head length, tarsus length, wing length, and body mass) measured on 291 breeding Imperial Shags at Punta León colony in coastal Patagonia, Argentina, during 2004 and 2005 breeding seasons. Discriminant analyses were performed on external measurements that we considered potentially useful in sexing Imperial Shags. All the birds were sexed by a distinctive behavior (vocalizations) and a sub-sample of fifty were also sexed by DNA-based genetic techniques, showing 100% agreement between the two methods. All measured characteristics differed between the sexes, with males being larger than females. Body mass (17.8 - 18.0%) and bill depth (12.8 - 13.2%) showed the highest level of dimorphism whereas bill, head, tarsus, and wing length were less dimorphic (ranging 4.8 - 6.0%). Dimorphism in body mass for breeding shags was lower than previously reported during winter, prior to the breeding season. Although the wing length showed the lowest degree of dimorphism (5.3 - 5.4%), it presented the lowest coefficient of variation (1.9 - 2.0%) resulting in the most accurate single-measurement indicating sex. A cross validation process with a new sample, revealed that discriminant functions comprised by two characteristics were more accurate and reliable for sex determination than single-measurements. We obtained two functions correctly classifying 94 - 97% of shags. These functions were reliable (similar accuracy for discriminant analysis, Jackknifed validation, and cross-validation with a new sample) and seasonal unbiased, as body mass was not included in the analysis.Fil: Svagelj, Walter Sergio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Quintana, Flavio Roberto. Wildlife Conservation Society; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaWaterbird Society2007-03info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/102934Svagelj, Walter Sergio; Quintana, Flavio Roberto; Sexual size dimorphism and sex determination by morphometric measurements in breeding Imperial Shags (Phalacrocorax atriceps); Waterbird Society; Waterbirds; 30; 1; 3-2007; 97-1021524-4695CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/http://www.bioone.org/doi/abs/10.1675/1524-4695%282007%29030%5B0097%3ASSDASD%5D2.0.CO%3B2info:eu-repo/semantics/altIdentifier/doi/10.1675/1524-4695(2007)030[0097:SSDASD]2.0.CO;2info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-03T10:06:23Zoai:ri.conicet.gov.ar:11336/102934instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-03 10:06:24.024CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse |
dc.title.none.fl_str_mv |
Sexual size dimorphism and sex determination by morphometric measurements in breeding Imperial Shags (Phalacrocorax atriceps) |
title |
Sexual size dimorphism and sex determination by morphometric measurements in breeding Imperial Shags (Phalacrocorax atriceps) |
spellingShingle |
Sexual size dimorphism and sex determination by morphometric measurements in breeding Imperial Shags (Phalacrocorax atriceps) Svagelj, Walter Sergio DISCRIMINANT ANALYSIS IMPERIAL SHAGS PHALACROCORACIDAE PHALACROCORAX ATRICEPS SEXUAL SIZE DIMORPHISM |
title_short |
Sexual size dimorphism and sex determination by morphometric measurements in breeding Imperial Shags (Phalacrocorax atriceps) |
title_full |
Sexual size dimorphism and sex determination by morphometric measurements in breeding Imperial Shags (Phalacrocorax atriceps) |
title_fullStr |
Sexual size dimorphism and sex determination by morphometric measurements in breeding Imperial Shags (Phalacrocorax atriceps) |
title_full_unstemmed |
Sexual size dimorphism and sex determination by morphometric measurements in breeding Imperial Shags (Phalacrocorax atriceps) |
title_sort |
Sexual size dimorphism and sex determination by morphometric measurements in breeding Imperial Shags (Phalacrocorax atriceps) |
dc.creator.none.fl_str_mv |
Svagelj, Walter Sergio Quintana, Flavio Roberto |
author |
Svagelj, Walter Sergio |
author_facet |
Svagelj, Walter Sergio Quintana, Flavio Roberto |
author_role |
author |
author2 |
Quintana, Flavio Roberto |
author2_role |
author |
dc.subject.none.fl_str_mv |
DISCRIMINANT ANALYSIS IMPERIAL SHAGS PHALACROCORACIDAE PHALACROCORAX ATRICEPS SEXUAL SIZE DIMORPHISM |
topic |
DISCRIMINANT ANALYSIS IMPERIAL SHAGS PHALACROCORACIDAE PHALACROCORAX ATRICEPS SEXUAL SIZE DIMORPHISM |
purl_subject.fl_str_mv |
https://purl.org/becyt/ford/1.6 https://purl.org/becyt/ford/1 |
dc.description.none.fl_txt_mv |
The Imperial Shag (Phalacrocorax atriceps) is monomorphic in plumage, but males are larger than females. We analyzed the sexual size dimorphism and variability of six morphometric characteristics (bill length, bill depth, head length, tarsus length, wing length, and body mass) measured on 291 breeding Imperial Shags at Punta León colony in coastal Patagonia, Argentina, during 2004 and 2005 breeding seasons. Discriminant analyses were performed on external measurements that we considered potentially useful in sexing Imperial Shags. All the birds were sexed by a distinctive behavior (vocalizations) and a sub-sample of fifty were also sexed by DNA-based genetic techniques, showing 100% agreement between the two methods. All measured characteristics differed between the sexes, with males being larger than females. Body mass (17.8 - 18.0%) and bill depth (12.8 - 13.2%) showed the highest level of dimorphism whereas bill, head, tarsus, and wing length were less dimorphic (ranging 4.8 - 6.0%). Dimorphism in body mass for breeding shags was lower than previously reported during winter, prior to the breeding season. Although the wing length showed the lowest degree of dimorphism (5.3 - 5.4%), it presented the lowest coefficient of variation (1.9 - 2.0%) resulting in the most accurate single-measurement indicating sex. A cross validation process with a new sample, revealed that discriminant functions comprised by two characteristics were more accurate and reliable for sex determination than single-measurements. We obtained two functions correctly classifying 94 - 97% of shags. These functions were reliable (similar accuracy for discriminant analysis, Jackknifed validation, and cross-validation with a new sample) and seasonal unbiased, as body mass was not included in the analysis. Fil: Svagelj, Walter Sergio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina Fil: Quintana, Flavio Roberto. Wildlife Conservation Society; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina |
description |
The Imperial Shag (Phalacrocorax atriceps) is monomorphic in plumage, but males are larger than females. We analyzed the sexual size dimorphism and variability of six morphometric characteristics (bill length, bill depth, head length, tarsus length, wing length, and body mass) measured on 291 breeding Imperial Shags at Punta León colony in coastal Patagonia, Argentina, during 2004 and 2005 breeding seasons. Discriminant analyses were performed on external measurements that we considered potentially useful in sexing Imperial Shags. All the birds were sexed by a distinctive behavior (vocalizations) and a sub-sample of fifty were also sexed by DNA-based genetic techniques, showing 100% agreement between the two methods. All measured characteristics differed between the sexes, with males being larger than females. Body mass (17.8 - 18.0%) and bill depth (12.8 - 13.2%) showed the highest level of dimorphism whereas bill, head, tarsus, and wing length were less dimorphic (ranging 4.8 - 6.0%). Dimorphism in body mass for breeding shags was lower than previously reported during winter, prior to the breeding season. Although the wing length showed the lowest degree of dimorphism (5.3 - 5.4%), it presented the lowest coefficient of variation (1.9 - 2.0%) resulting in the most accurate single-measurement indicating sex. A cross validation process with a new sample, revealed that discriminant functions comprised by two characteristics were more accurate and reliable for sex determination than single-measurements. We obtained two functions correctly classifying 94 - 97% of shags. These functions were reliable (similar accuracy for discriminant analysis, Jackknifed validation, and cross-validation with a new sample) and seasonal unbiased, as body mass was not included in the analysis. |
publishDate |
2007 |
dc.date.none.fl_str_mv |
2007-03 |
dc.type.none.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion http://purl.org/coar/resource_type/c_6501 info:ar-repo/semantics/articulo |
format |
article |
status_str |
publishedVersion |
dc.identifier.none.fl_str_mv |
http://hdl.handle.net/11336/102934 Svagelj, Walter Sergio; Quintana, Flavio Roberto; Sexual size dimorphism and sex determination by morphometric measurements in breeding Imperial Shags (Phalacrocorax atriceps); Waterbird Society; Waterbirds; 30; 1; 3-2007; 97-102 1524-4695 CONICET Digital CONICET |
url |
http://hdl.handle.net/11336/102934 |
identifier_str_mv |
Svagelj, Walter Sergio; Quintana, Flavio Roberto; Sexual size dimorphism and sex determination by morphometric measurements in breeding Imperial Shags (Phalacrocorax atriceps); Waterbird Society; Waterbirds; 30; 1; 3-2007; 97-102 1524-4695 CONICET Digital CONICET |
dc.language.none.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
info:eu-repo/semantics/altIdentifier/url/http://www.bioone.org/doi/abs/10.1675/1524-4695%282007%29030%5B0097%3ASSDASD%5D2.0.CO%3B2 info:eu-repo/semantics/altIdentifier/doi/10.1675/1524-4695(2007)030[0097:SSDASD]2.0.CO;2 |
dc.rights.none.fl_str_mv |
info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by-nc-sa/2.5/ar/ |
eu_rights_str_mv |
openAccess |
rights_invalid_str_mv |
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/ |
dc.format.none.fl_str_mv |
application/pdf application/pdf application/pdf |
dc.publisher.none.fl_str_mv |
Waterbird Society |
publisher.none.fl_str_mv |
Waterbird Society |
dc.source.none.fl_str_mv |
reponame:CONICET Digital (CONICET) instname:Consejo Nacional de Investigaciones Científicas y Técnicas |
reponame_str |
CONICET Digital (CONICET) |
collection |
CONICET Digital (CONICET) |
instname_str |
Consejo Nacional de Investigaciones Científicas y Técnicas |
repository.name.fl_str_mv |
CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas |
repository.mail.fl_str_mv |
dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar |
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1842269956662624256 |
score |
13.13397 |